1. Field of the Invention
The present invention relates to an accessory or fitting for a baking oven and a cooking vessel or dish for it. This sort of accessory or fitting typically can be a broiler grid, a fat collecting dish, a baking pan or a cooking or baking dish. Typically the vessel or dish can be a riser mold, a roasting vessel, a pot or the like. The present invention also relates to methods of cooking in a pyrolytically self-cleaning baking oven with a baking oven accessory and a baking oven cooking vessel and of cleaning both the oven accessory and cooking vessel as well as the baking oven.
2. Prior Art
Pyrolysis self-cleaning of baking ovens is currently widespread. Overflowing and burned-on food residues are turned to ash by pyrolysis at temperatures of typically 500xc2x0 C. and can subsequently be wiped out with a moist towel or rag. Currently accessories for baking ovens and cooking vessels for them, which are made from aluminum sheet, enameled steel sheet or chromium grid rods in grids, must be removed from baking ovens during the pyrolysis self-cleaning of the baking ovens, since the pyrolysis temperature would make the accessories and the cooking vessels unuseable because of strong warping and/or oxidation. Glass baking dishes may be used only up to a maximum temperature of 250xc2x0 C.
Because of this aspect of the currently used baking oven accessories and vessels or dishes for them burned-on food residues on the baking oven accessories or the cooking vessels or dishes must be removed from them by hand during a separate cleaning operation. Besides the considerable time consumed and the not inconsiderable water consumption occurring in this separate cleaning process often strong abrasive means or a scrubbing sponge or steel wool must be used. As a result scratches are produced on the metal accessories or vessels, which promote burning on, for example in baking vessels in the next baking process.
Especially in commercial applications outside of private applications, e.g. in bakeries, pizza baking concerns, restaurants, etc., these special cleaning efforts for baking oven accessories and vessels are a considerable disadvantage.
It is an object of the present invention to provide an improved method of cooking with a self-cleaning baking oven with an oven accessory and cooking vessel and of cleaning the oven accessory and cooking vessel as well as the baking oven, in which the oven accessory and cooking vessel are made from materials that prevent damage to the oven accessory and cooking vessel when they are placed in the baking oven during pyrolysis self-cleaning in order to eliminate the required separate cleaning processes for the self-cleaning baking oven and the oven accessory and cooking vessel.
According to the invention the method for cooking in and subsequent cleaning of a pyrolytically self-cleaning baking oven and of baking oven accessories and of baking oven cooking vessels used in cooking in the baking oven, comprises the steps of:
a) providing a baking oven accessory and a baking oven cooking vessel for cooking in the self-cleaning baking oven, said baking oven accessory and baking oven cooking vessel consisting of respective materials having as small as possible a coefficient of linear thermal expansion and sufficient temperature stability to remain without damage in the self-cleaning oven during pyrolytic self-cleaning of the self-cleaning oven;
b) cooking in the self-cleaning oven with the baking oven accessory and the baking oven cooking vessel provided in step a); and
c) pyrolytically self-cleaning the self-cleaning baking oven with the baking oven accessory and the baking oven cooking vessel within the self-cleaning baking oven during the self-cleaning in order to clean the baking oven accessory and baking oven cooking vessel as well as the self-cleaning baking oven;
whereby a separate manual cleaning of the baking oven accessory and the baking oven cooking vessel is eliminated.
According to the invention, the accessory for a baking oven and the cooking vessel or dish placed on it or for it are made from a material that has a sufficiently high temperature stability at the high pyrolysis temperatures occurring during pyrolysis self-cleaning in baking ovens, e.g. at a pyrolysis temperature of about 500xc2x0 C., so that the cooking vessels or dishes and the accessories can be left in the baking oven during the pyrolysis self-cleaning, and that has as small as possible a thermal linear expansion coefficient.
The baking oven accessories and cooking vessels or dishes used on them according to the invention have the advantage that they can remain in the oven during pyrolysis self-cleaning of the baking oven so that they are cleaned at the same time as the oven. A troublesome manual cleaning of the cooking residue from the accessories and vessels or dishes is thus eliminated.
The so-called baking oven accessories and cooking vessels or dishes can be used in baking ovens in private households and in commercial establishments. They can be advantageously used as tempering ovens in scientific and engineering laboratories.
According to a preferred embodiment of the invention the accessories for the baking oven and the cooking vessels or dishes for it are made from glass, glass-ceramic or ceramic material with a thermal linear expansion coefficient less than or equal to 3xc3x9710xe2x88x926/K.
The glass-ceramic material used for the accessories and vessels or dishes should have a specific thermal stress of  less than 0.25 MPa/K with a temperature stability  greater than 500xc2x0 C. or of  less than 0.23 MPa/K with a temperature stability of  greater than 550xc2x0 C.
The baking dishes and baking pans are preferably formed from the foregoing type of materials.
According to a further aspect of the invention the material for the accessories and vessels or dishes for the baking oven can be a superior quartz-mixed-crystal glass-ceramic material, which can be transparent or colored, preferably dark. According to another aspect the material can be a keatite-mixed-crystal glass-ceramic material, which can be opaque, white or colored.
The high radiation permeability from above during pyrolysis heating is the essential advantage obtained by using glass-ceramic material.
According to another preferred embodiment the accessories for the baking oven can be made from a ceramic material with comparatively little surface porosity, preferably as little surface porosity as possible. This ceramic material is preferably aluminum oxide. Thus a broiler grid can be made from ceramic rods or tubes as well as dishes and pans.
According to a third preferred embodiment of the invention the accessories for the baking oven and the cooking vessels or dishes placed on them are made from a high temperature-stable metallic alloy with reduced linear thermal expansion coefficient. This metallic alloy can be a chromium-nickel alloy or an iron-nickel alloy, especially an alloy that is marketed under the tradename INVAR. This metallic material is especially suitable for broiler grids.